Weber 38/38 DGES

[akawes]

Has anyone used this carb? also what are the pros and cons of running this vs a dual IDF setup?

[So Cal Mark]

we currently have them on two customer cars. Since they are a synchronous carb, there is a short learning curve on how to drive the car with that carb. You can't floor the throttle at low rpm, but you can accelerate really quickly. The carb has a great top end. The pros compared to dual idf's would be not having to synchronize two carbs, but that isn't really difficult. Initially you only have to buy one carb instead of two

[bradartigue]

Has anyone used this carb? also what are the pros and cons of running this vs a dual IDF setup?

They aren't the same driving experience as dual IDFs. The individual throttles on each intake creates a very different driving experience with IDFs, whereas with downdrafts you get a less linear surge. Of course the big Webers are synchronous, as described above, so the two-stage acceleration you'll experience with a normal downdraft isn't there. The single carb is easy to tune, unlike IDFs, and stays in tune, unlike IDFs, and is far more refined, unlike IDFs.

I personally think it is too much carburetor for a TC motor unless you have some significant modifications. Otherwise you will be detuning it to compensate, and ending up with a strangled 38 as opposed to, say, a properly fitted 34ADF or 36ADL. BTW you can make both of those carburetors synchronous by adjusting the throttle linkages, and it is a real kick in the ass. Fouls plugs like crazy if you're not careful, and washes your piston bores with gas.

[akawes]

I'm actually going to pull the motor in a couple weeks and do an engine rebuuild. and do the works.

[So Cal Mark]

I would only recommend that carb for a 2L with some perf mods

[akawes]

so what would you recommend for the 1.8L with performance mods. and what bore size is the safest to go to for high comp pistons?

[bradartigue]

so what would you recommend for the 1.8L with performance mods. and what bore size is the safest to go to for high comp pistons?

Bore size is going to be determined by the current condition of your bores; you'll want a machine shop to inspect the bores after they hone them and give you an idea. At least I like for the shop to hone them first, it reveals pits so much better than just inspecting. Then they cut if necessary and re-hone.

Lots of folks run 9.8:1 CR pistons without any issues. I ran 9.1:1 CR pistons on a fuel injected 2000 and 8.9:1 CR on a fuel injected 1800 (L-Jet swapped over) and enjoyed them immensely. I never ran 9.8:1 only because when I was swapping pistons on cars the lower CR ones were available; I don't know what is available today.

[BrwnRecluse]

I have a Weber 38 on my 1987 Mazda B2200. Other mods are a bigger cam, bored out, header, etc. There is a difference between the 38 and the 32/36, with better acceleration, but the cam went in at the same time so it's hard to tell which had the most effect. That said, the 38 dropped my fuel econmy 5mpg. But it's a blast to drive!

[akawes]

5 miles per gallon with an 13 and a half gallon tank could be an issue lol.

[BrwnRecluse]

My bad. I meant went from 26 mpg to 19-21 mpg

[akawes]

I'm sorry I misread your last post. I thought you said 5 total mpg. My bad.

[baltobernie]

I finally gave up on the Weber 38 DG_S after two years and hundreds of dollars in jets, dyno time and a wideband A/F meter. This carb is designed for 2.8 and 3.0 V-6 engines. My motor is 1796cc, HC pistons, single-plane intake and 80/40 cams dialed-in. I'm now running a 36 DCD 14 with 25/27 chokes. (The 38 DG_S is 27/27). I can detect no difference in top-end power between the two carbs, and the progressive nature of the DCD make for a much more enjoyable drive. You need a lot of vacuum to pull in the main circuit of the 38 in an engine under 2L, and if you're running performance cams, low-end vacuum is sacrificed for mid- and top-end performance. I could never tune out the stumble around 1500 RPM. Maybe changing emulsion tubes would have got me there, but the DCD was bolt-on and go. I'm up two sizes in primary main jet, but everything else (so far) is unchanged.

I'd recommend the manual choke DCD for new single-carb applications on Spiders with non-stock cams, and the 32/36DGEV for stock cam engines and an automatic choke. Brad's 34ADF or 36ADL were FIAT's choices, too, and would allow you to use the stock air filter. The DCD requires a 1-3/4" K&N.